/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrBlurUtils_DEFINED
#define GrBlurUtils_DEFINED

#include "include/core/SkRefCnt.h"
#include "include/core/SkScalar.h"
#include "src/gpu/SkBackingFit.h"

#include <memory>

class GrClip;
class GrPaint;
class GrRecordingContext;
class GrStyledShape;
class GrSurfaceProxyView;
class SkColorSpace;
class SkMaskFilter;
class SkMatrix;
class SkPaint;
class SkRRect;
enum SkAlphaType : int;
enum class GrColorType;
enum class SkTileMode;
namespace skgpu {
namespace ganesh {
class SurfaceDrawContext;
}
}
struct SkIRect;
struct SkISize;

/* *
 * Blur utilities.
 */
namespace GrBlurUtils {
static constexpr int kBlurRRectMaxDivisions = 6;

/* *
 * This method computes all the parameters for drawing a partially occluded nine-patched
 * blurred rrect mask:
 * rrectToDraw - the integerized rrect to draw in the mask
 * widthHeight - how large to make the mask (rrectToDraw will be centered in this coord system).
 * rectXs, rectYs - the x & y coordinates of the covering geometry lattice
 * texXs, texYs - the texture coordinate at each point in rectXs & rectYs
 * It returns true if 'devRRect' is nine-patchable
 */
bool ComputeBlurredRRectParams(const SkRRect &srcRRect, const SkRRect &devRRect, SkScalar sigma, SkScalar xformedSigma,
    SkRRect *rrectToDraw, SkISize *widthHeight, SkScalar rectXs[kBlurRRectMaxDivisions],
    SkScalar rectYs[kBlurRRectMaxDivisions], SkScalar texXs[kBlurRRectMaxDivisions],
    SkScalar texYs[kBlurRRectMaxDivisions]);

/* *
 * Draw a shape handling the mask filter if present.
 */
void DrawShapeWithMaskFilter(GrRecordingContext *, skgpu::ganesh::SurfaceDrawContext *, const GrClip *, const SkPaint &,
    const SkMatrix &, const GrStyledShape &);

/* *
 * Draw a shape handling the mask filter. The mask filter is not optional.
 * The GrPaint will be modified after return.
 */
void DrawShapeWithMaskFilter(GrRecordingContext *, skgpu::ganesh::SurfaceDrawContext *, const GrClip *,
    const GrStyledShape &, GrPaint &&, const SkMatrix &viewMatrix, const SkMaskFilter *);

/* *
 * Applies a 2D Gaussian blur to a given texture. The blurred result is returned
 * as a surfaceDrawContext in case the caller wishes to draw into the result.
 * The GrSurfaceOrigin of the result will watch the GrSurfaceOrigin of srcView. The output
 * color type, color space, and alpha type will be the same as the src.
 *
 * Note: one of sigmaX and sigmaY should be non-zero!
 * @param context         The GPU context
 * @param srcView         The source to be blurred.
 * @param srcColorType    The colorType of srcProxy
 * @param srcAlphaType    The alphaType of srcProxy
 * @param srcColorSpace   Color space of the source.
 * @param dstBounds       The destination bounds, relative to the source texture.
 * @param srcBounds       The source bounds, relative to the source texture's offset. No pixels
 * will be sampled outside of this rectangle.
 * @param sigmaX          The blur's standard deviation in X.
 * @param sigmaY          The blur's standard deviation in Y.
 * @param tileMode        The mode to handle samples outside bounds.
 * @param fit             backing fit for the returned render target context
 * @return                The surfaceDrawContext containing the blurred result.
 */
std::unique_ptr<skgpu::ganesh::SurfaceDrawContext> GaussianBlur(GrRecordingContext *, GrSurfaceProxyView srcView,
    GrColorType srcColorType, SkAlphaType srcAlphaType, sk_sp<SkColorSpace> srcColorSpace, SkIRect dstBounds,
    SkIRect srcBounds, float sigmaX, float sigmaY, SkTileMode mode, SkBackingFit fit = SkBackingFit::kApprox);
} // namespace GrBlurUtils

#endif
